feat: add diagnostic interview loop

internal/httpapi/diagnostic.go

@@ -0,0 +1,80 @@
+package httpapi
+
+import (
+	"encoding/json"
+	"errors"
+	"net/http"
+
+	"tutor/internal/interview"
+)
+
+type createDiagnosticSessionRequest struct {
+	UserID            string   `json:"user_id"`
+	TargetRole        string   `json:"target_role"`
+	Stack             []string `json:"stack"`
+	InterviewTimeline string   `json:"interview_timeline"`
+}
+
+type submitDiagnosticAnswerRequest struct {
+	QuestionID string `json:"question_id"`
+	AnswerText string `json:"answer_text"`
+}
+
+func (h Handler) createDiagnosticSession(w http.ResponseWriter, r *http.Request) {
+	var req createDiagnosticSessionRequest
+	if err := json.NewDecoder(r.Body).Decode(&req); err != nil {
+		writeError(w, http.StatusBadRequest, "invalid JSON body")
+		return
+	}
+
+	session, err := h.diagnostic.CreateSession(r.Context(), interview.CreateSessionInput{
+		UserID:            req.UserID,
+		TargetRole:        req.TargetRole,
+		Stack:             req.Stack,
+		InterviewTimeline: req.InterviewTimeline,
+	})
+	if err != nil {
+		writeError(w, http.StatusBadRequest, err.Error())
+		return
+	}
+
+	writeJSON(w, http.StatusCreated, session)
+}
+
+func (h Handler) getDiagnosticSession(w http.ResponseWriter, r *http.Request) {
+	session, err := h.diagnostic.GetSession(r.PathValue("id"))
+	if errors.Is(err, interview.ErrSessionNotFound) {
+		writeError(w, http.StatusNotFound, "diagnostic session not found")
+		return
+	}
+	if err != nil {
+		writeError(w, http.StatusInternalServerError, "could not load diagnostic session")
+		return
+	}
+
+	writeJSON(w, http.StatusOK, session)
+}
+
+func (h Handler) submitDiagnosticAnswer(w http.ResponseWriter, r *http.Request) {
+	var req submitDiagnosticAnswerRequest
+	if err := json.NewDecoder(r.Body).Decode(&req); err != nil {
+		writeError(w, http.StatusBadRequest, "invalid JSON body")
+		return
+	}
+
+	answer, err := h.diagnostic.SubmitAnswer(r.Context(), interview.SubmitAnswerInput{
+		SessionID:  r.PathValue("id"),
+		QuestionID: req.QuestionID,
+		AnswerText: req.AnswerText,
+	})
+	if errors.Is(err, interview.ErrSessionNotFound) || errors.Is(err, interview.ErrQuestionNotFound) {
+		writeError(w, http.StatusNotFound, err.Error())
+		return
+	}
+	if err != nil {
+		writeError(w, http.StatusBadRequest, err.Error())
+		return
+	}
+
+	writeJSON(w, http.StatusCreated, answer)
+}